1. Field of the Invention
The present invention relates to a standardized digital transmission system that transmits digital video signals on which digital audio signals are multiplexed for a predetermined period, and more specifically, to a video signal receiving device and a video signal receiving method that receive transmitted digital video signals and carry out a specific control to digital audio signals.
2. Description of the Related Art
It is known that as a standard to transmit digital video signals, digital visual interface (DVI) standard has spread. In recent years, as a digital signal transmission standard further improved from the DVI standard, high definition multimedia interface (HDMI) standard has come to be adopted.
In the HDMI standard, various standards that are not specified in the DVI standard, such as, for example, that digital audio signals are multiplexed in a blanking period of digital video signals, thereby enabling audio transmission, that digital video signals can be transmitted in color difference YCbCr format as well as RGB format, that connection can be made by a universal serial bus (USB)-like small HDMI connector, and so forth, are specified.
Therefore, in configuring a digital transmission system in conformity to the HDMI standard, it is necessary to consider various aspects that have not been in transmission systems conforming to the DVI standard. For example, in the HDMI standard, audio transmission is available. Accordingly, if an HDMI connector is pulled or inserted while audio is received, or if audio signals change greatly, unpleasant noises such as a buzz noise or the like come out, which has been a problem in the prior art.
Jpn. Pat. Appln. KOKAI Publication No. 7-236101discloses a configuration for preventing a buzz noise from occurring owing to discontinuity of audio data, and digital switching of data processing. Further, Jpn. Pat. Appln. KOKAI Publication No. 2000-314970discloses a configuration of a system conforming to the DVI standard in which a source device side is controlled from a synch device side.
However, in these patent publications, there is no description concerning countermeasures against the occurrence of unpleasant noises at a receiver side in a digital transmission system conforming to the HDMI standard.